• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.3
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• pp.93-98
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• 2005

STSAT-2 will be launched on December 2007 by the first Korean launch vehicle KSLV-1, and its one of the main instruments is DREAM (Dual Channel Radio Frequency and Environment Atmosphere Monitoring) which detects a signal for atmosphere from the Earth by using micro-wave signal. The STSAT-2 has many units for technology demonstration such as FDSS (Fine Digital Sun Sensor) and DHST (Dual Head Star Tracker) including PPT (Pulsed Plasma Thruster) for attitude control and momentum dumping in the space. In this paper, the power budget analysis for STSAT-2 will be studied and provided for supporting the whole mission life time during the mission of its spacecraft.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.11
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• pp.2932-2941
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• 1996

Conventional non-regenerative satellite repeaters do not provide anti-jamming capability enough to provide communications between small terminals in jamming environment. In this paper, we analyze the budget and system requirements for Ka-band satellite communication. For the analysis, we modeled and simulated the Ka-band satellite system based on downlink power limited repeater. Assuming that a spread spectrum is applied for anti-jamming purpose, we also analyzed a tolerable jammer-to-signal power ratio under strong up-link jamming in the bit rates of 2.4Kbps and 19.6Kbps.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.45-50
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• 2002

A conceptual design on the link budget of TC&R RF subsystem which transfers command and telemetry data as RF signal between the ground system and the 2005SAT spacecraft is presented in this paper. In order to perform the analysis of the link budget, we divided the analysis process into two processes, i.e., uplink and downlink process. For the uplink the power flux density at the spacecraft and the margin of the command receiver are calculated. In the case of the downlink the downlink EIRP and the margin of C/ No and Eb / No at the ground station are calculated. Through the uplink performance analysis, the power at the command receiver has well efficient margin, and the margin of C/ No and Eb / No is also fully proper for the downlink case.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.1-7
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• 2010

The reliability of a power system has close relationship with the maintenance of the distribution systems. This paper presents the method of the maintenance planning of the distribution systems by minimizing the interruption cost. The interruption cost for the equipment failures is formulated using time varying failure rate and minimized by optimization of the object function. The proposed method provides the priority list for the investment of the maintenance subject to the limited investment budget by the economic analysis. In order to test the proposed method, the modified distribution system of a rural area is introduced for the testing system. Test results show that the proposed method is good enough by evaluating the improvement of the reliability of the power system.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.561-564
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• 2004

The motion estimation which requires huge computation consumes large power in a video encoder. Although a number of fast-search algorithms are proposed to reduce the power consumption, the smaller the computation, the worse the performance they have. In this paper, we propose an architecture that a low energy management scheme can be applied with several fast-search algorithm. In addition. we show that ECVH, a software scheduling scheme which dynamically changes the search algorithm, the operating frequency, and the supply voltage using the remaining slack time within given power-budget, can be applied to the architecture, and show that the power consumption can be reduced.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.609-620
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• 2017

We studied the value of a nuclear power plant by considering Koreans' willingness to pay (WTP) for neutralizing the various problems caused by building and operating a new plant. For this, we used a conjoint analysis and ordered logistic regression. We then compared the WTP estimates between various segment groups. The results revealed that each household was willing to pay an additional 99,677 Korean Won (KRW)/mo on average to resolve the negative impacts from a nuclear plant. Therefore, the yearly cognitive and economic value of a nuclear plant in Korea was about 19 trillion KRW. Through a segment analysis, we found that the more educated, younger, and poorer groups gave higher cognitive values than the less educated, older, and richer groups, respectively. Also, people who lived far from a plant gave higher values than people living near a plant, and people with more knowledge about or interest in nuclear energy gave higher values than people with less knowledge or interest. People who felt that nuclear energy is necessary gave higher values to nuclear energy than those who did not. Our results can be used as bases to set targets for promoting nuclear energy and pursuing a national project of building a nuclear power plant.

• Journal of computational fluids engineering
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• v.12 no.3
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• pp.62-68
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• 2007

A conceptual thermal design is performed for the optical payload system of a geostationary satellite. The optical payload considered in this paper is GOCI(Geostationary Ocean Color Imager) of COMS of Korea. The radiative thermal control system is employed in order to expect a small thermal gradient in the telescope structure of GOCl. Two design margins are applied to the dedicated radiator dimensioning, and three kinds of configuration to the heater power sizing. A Monte-Carlo ray tracing method and a network analysis method are utilized to calculate radiative couplings and thermal responses respectively. At the level of conceptual design, sizing thresholds are presented for the radiator and heater on the purpose of determining the mass and power budget of the spacecraft.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.79-80
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• 2015

With the government's support for new and renewable energy, photovoltaic equipment has rapidly been supplied. However, compared to supply rate, maintenance has not supported enough and relevant research has not much conducted. Therefore, the purpose of this study is to analyze maintenance effectiveness of photovoltaic equipment. What is the most important in maintenance effectiveness is a rise in power generation. It was estimated that if photovoltaic equipment for detached houses is maintained well, power generation increases by 4.0% at least, and by 6.5% on average. As a result, it was analyzed that it is necessary to maximize the effectiveness of the government's budget investment through well maintenance of photovoltaic equipment for detached houses.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.26 no.4
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• pp.296-309
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• 2022

Timer options are one of the contingent claims that, for given the variance budget, its payoff depends on a random maturity in terms of the realized variance unlike the standard European vanilla option with a fixed time maturity. Since it was first launched by Société Générale Corporate and Investment Banking in 2007, the valuation of the timer options under several stochastic environment for the volatility has been conducted by many researches. In this study, we propose the pricing of timer power options combined with standard timer options and the index of the power to the underlying asset for the investors to actualize lower risks and higher returns at the same time under the uncertain markets. By using the asymptotic analysis, we obtain the first-order approximation of timer power options. Moreover, we demonstrate that our solution has been derived accurately by comparing it with the solution from the Monte-Carlo method. Finally, we analyze the impact of the stochastic volatility with regards to various parameters on the timer power options numerically.

• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.145-151
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• 2018

Objectives: The purpose of this study was to interpret regional disparities in the number of teeth sealed with pit and fissure sealants, identify the factors that affect these disparities and find solutions for the same. Methods: Data were collected from the National Health Insurance Service and Korean statistical information service using metropolis-city-rural area dental health infrastructure variables, regional health behavior variables, and local finance-related variables. Results: In 2015, the number of teeth sealed with pit and fissure sealants per 100 people was higher in the metropolis or city than in the rural area. There was a positive correlation between the number of teeth sealed with pit and fissure sealants and the number of dentists, dental hygienists, dental institutions, standardization rate of subjective awareness of well-being, standardization rate of brushing after lunch, and the proportion of welfare budget in the general budget. There was a negative correlation with the annual standardization rate of health institution use, the standardization rate of unused medical services, and the local government's financial independence. According to the final model of the multiple regression analysis, while the impact of infrastructure on dentistry was not statistically significant, the statistical significance of standardization rate of brushing after lunch, the local government's financial independence, and the proportion of welfare budget in the general budget were maintained. Conclusions: To reduce regional disparities in the volume of use of pit and fissure sealants, it was concluded that it may be effective to select regions with a consideration of the level of regional economic power, implement separate and appropriate policies and projects, and improve the awareness in residents.